Liquefracture handpiece

ABSTRACT

A surgical handpiece having two coaxial tubes or channels mounted within a body. The first tube is used for aspiration and is smaller in diameter than the second tube so as to create an annular passage between the first and second tube. The annular passage communicates with a pumping chamber formed between two electrodes. The pumping chamber works by boiling a small volume of the surgical fluid. As the fluid boils, it expands rapidly, thereby propelling the liquid downstream of the pumping chamber out of the annular passage. The distal end of the annular gap is sealed by sealing together the distal ends of the first and second tube and a plurality or orifices or ports may be formed near the seal. As the expanding gas is propelled down the annular gap, the gas/liquid stream is forced out of the distal orifices in a controlled and directed manner.

This application is a continuation-in-part application of U.S. Pat.application Ser. No. 09/090,433, filed Jun. 4, 1998, now U.S. Pat. No.6,080,128.

BACKGROUND OF THE INVENTION

This invention relates generally to the field of cataract surgery andmore particularly to a handpiece tip for practicing the liquefracturetechnique of cataract removal.

The human eye in its simplest terms functions to provide vision bytransmitting light through a clear outer portion called the cornea, andfocusing the image by way of the lens onto the retina. The quality ofthe focused image depends on many factors including the size and shapeof the eye, and the transparency of the cornea and lens.

When age or disease causes the lens to become less transparent, visiondeteriorates because of the diminished light which can be transmitted tothe retina. This deficiency in the lens of the eye is medically known asa cataract. An accepted treatment for this condition is surgical removalof the lens and replacement of the lens function by an artificialintraocular lens (IOL).

In the United States, the majority of cataractous lenses are removed bya surgical technique called phacoemulsification. During this procedure,a thin phacoemulsification cutting tip is inserted into the diseasedlens and vibrated ultrasonically. The vibrating cutting tip liquifies oremulsifies the lens so that the lens may be aspirated out of the eye.The diseased lens, once removed, is replaced by an artificial lens.

A typical ultrasonic surgical device suitable for ophthalmic proceduresconsists of an ultrasonically driven handpiece, an attached cutting tip,and irrigating sleeve and an electronic control console. The handpieceassembly is attached to the control console by an electric cable andflexible tubes. Through the electric cable, the console varies the powerlevel transmitted by the handpiece to the attached cutting tip and theflexible tubes supply irrigation fluid to and draw aspiration fluid fromthe eye through the handpiece assembly.

The operative part of the handpiece is a centrally located, hollowresonating bar or horn directly attached to a set of piezoelectriccrystals. The crystals supply the required ultrasonic vibration neededto drive both the horn and the attached cutting tip duringphacoemulsification and are controlled by the console. The crystal/hornassembly is suspended within the hollow body or shell of the handpieceby flexible mountings. The handpiece body terminates in a reduceddiameter portion or nosecone at the body's distal end. The nosecone isexternally threaded to accept the irrigation sleeve. Likewise, the hornbore is internally threaded at its distal end to receive the externalthreads of the cutting tip. The irrigation sleeve also has an internallythreaded bore that is screwed onto the external threads of the nosecone.The cutting tip is adjusted so that the tip projects only apredetermined amount past the open end of the irrigating sleeve.Ultrasonic handpieces and cutting tips are more fully described in U.S.Pat. Nos. 3,589,363; 4,223,676; 4,246,902; 4,493,694; 4,515,583;4,589,415; 4,609,368; 4,869,715; 4,922,902; 4,989,583; 5,154,694 and5,359,996, the entire contents of which are incorporated herein byreference.

In use, the ends of the cutting tip and irrigating sleeve are insertedinto a small incision of predetermined width in the cornea, sclera, orother location. The cutting tip is ultrasonically vibrated along itslongitudinal axis within the irrigating sleeve by the crystal-drivenultrasonic horn, thereby emulsifying the selected tissue in situ. Thehollow bore of the cutting tip communicates with the bore in the hornthat in turn communicates with the aspiration line from the handpiece tothe console. A reduced pressure or vacuum source in the console draws oraspirates the emulsified tissue from the eye through the open end of thecutting tip, the cutting tip and horn bores and the aspiration line andinto a collection device. The aspiration of emulsified tissue is aidedby a saline flushing solution or irrigant that is injected into thesurgical site through the small annular gap between the inside surfaceof the irrigating sleeve and the cutting tip.

Recently, a new cataract removal technique has been developed thatinvolves the injection of hot (approximately 45° C. to 105° C.) water orsaline to liquefy or gellate the hard lens nucleus, thereby making itpossible to aspirate the liquefied lens from the eye. Aspiration isconducted concurrently with the injection of the heated solution and theinjection of a relatively cool solution, thereby quickly cooling andremoving the heated solution. This technique is more fully described inU.S. Pat. No. 5,616,120 (Andrew, et al.), the entire content of which isincorporated herein by reference. The apparatus disclosed in thepublication, however, heats the solution separately from the surgicalhandpiece. Temperature control of the heated solution can be difficultbecause the fluid tubes feeding the handpiece typically are up to twometers long, and the heated solution can cool considerably as it travelsdown the length of the tube.

U.S. Pat. No. 5,885,243 (Capetan, et al.) discloses a handpiece having aseparate pumping mechanism and resistive heating element. Such astructure adds unnecessary complexity to the handpiece.

Therefore, a need continues to exist for a simple surgical handpiece andtip that can heat internally the solution used to perform theliquefracture technique.

BRIEF SUMMARY OF THE INVENTION

The present invention improves upon the prior art by providing asurgical handpiece having two coaxially mounted tubes or channelsmounted to a body. The first tube is used for aspiration and is smallerin diameter than the second tube so as to create an annular passagebetween the first and second tube. The annular gap communicates with apumping chamber formed between two electrodes. The pumping chamber worksby boiling a small volume of the surgical fluid. As the fluid boils, itexpands rapidly, thereby propelling the liquid downstream of the pumpingchamber out of the annular gap. The distal end of the annular gap issealed by sealing together the distal ends of the first and second tubeand a plurality or orifices or ports may be formed near the seal. As theexpanding gas is propelled down the annular gap, the gas/liquid streamis forced out of the distal ports in a controlled and directed manner.

Accordingly, one objective of the present invention is to provide asurgical handpiece having at least two coaxial tubes.

Another objective of the present invention is to provide a handpiecehaving a pumping chamber.

Another objective of the present invention is to provide a surgicalhandpiece having a device for delivering the surgical fluid through thehandpiece in pulses.

Still another objective of the present invention is to provide ahandpiece having a pumping chamber formed by two electrodes.

Yet another objective of the present invention is to provide a handpiecehaving two electrodes wherein the electrodes are insulated.

Still another objective of the present invention is to provide ahandpiece that delivers fluid pulses in a controlled and directedmanner.

These and other advantages and objectives of the present invention willbecome apparent from the detailed description and claims that follow.

BREIF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front, upper left perspective view of a first embodiment ofthe handpiece of the present invention.

FIG. 2 is a rear, upper right perspective view of a first embodiment ofthe handpiece of the present invention.

FIG. 3 is a cross-sectional view of a first embodiment of the handpieceof the present invention taken along a plane passing through theirrigation channel.

FIG. 4 is a cross-sectional view of a first embodiment of the handpieceof the present invention taken along a plane passing through theaspiration channel.

FIG. 5 is an enlarged partial cross-sectional view of a first embodimentof the handpiece of the present invention taken at circle 5 in FIG. 4.

FIG. 6 is an enlarged partial cross-sectional view of a first embodimentof the handpiece of the present invention taken at circle 6 in FIG. 3.

FIG. 7 is an enlarged cross-sectional view of a first embodiment of thehandpiece of the present invention taken at circle 7 in FIGS. 3 and 4.

FIG. 8 is a partial cross-sectional view of a second embodiment of thehandpiece of the present invention.

FIG. 9 is an enlarged partial cross-sectional view of the secondembodiment of the handpiece of the present invention taken at circle 9in FIG. 8.

FIG. 10 is an enlarged partial cross-sectional view of the pumpingchamber used in the second embodiment of the handpiece of the presentinvention taken at circle 10 in FIG. 9.

FIG. 11 is a partial cross-sectional view of a third embodiment of thehandpiece of the present invention.

FIG. 12 is an enlarged partial cross-sectional view of the distal end ofthe third embodiment of the handpiece of the present invention taken atcircle 12 in FIG. 11.

FIG. 13 is an enlarged partial cross-sectional view of the pumpingchamber used in the third embodiment of the handpiece of the presentinvention shown in FIGS. 11 and 12.

FIG. 14 is a front perspective view of one embodiment of a distal tipthat may be used with the handpiece of the present invention.

FIG. 15 is a front perspective view of a second embodiment of a distaltip that may be used with the handpiece of the present invention.

FIG. 16 is a front perspective view of a third embodiment of a distaltip that may be used with the handpiece of the present invention.

FIG. 17 is a front perspective view of a fourth embodiment of a distaltip that may be used with the handpiece of the present invention.

FIG. 18 is a front perspective view of a fifth embodiment of a distaltip that may be used with the handpiece of the present invention.

FIG. 19 is a longitudinal cross-sectional view of the tip illustrated inFIG. 18.

FIG. 20A is a front perspective view of a sixth embodiment of a distaltip that may be used with the handpiece of the present inventionoperating at high pressure with a short coherence length.

FIG. 20B is a front perspective view of a sixth embodiment of a distaltip that may be used with the handpiece of the present inventionoperating at low pressure with a long coherence length.

FIG. 21 is a block diagram of a control system that can be used with thehandpiece of the present invention.

DETAILED DESCIRPTION OF THE INVENTION

Handpiece 10 of the present invention generally includes handpiece body12 and operative tip 16. Body 12 generally includes external irrigationtube 18 and aspiration fitting 20. Body 12 is similar in construction towell-known in the art phacoemulsification handpieces and may be madefrom plastic, titanium or stainless steel. As best seen in FIG. 6,operative tip 16 includes tip/cap sleeve 26, needle 28 and tube 30.Sleeve 26 may be any suitable commercially available phacoemulsificationtip/cap sleeve or sleeve 26 may be incorporated into other tubes as amulti-lumen tube. Needle 28 may be any commercially available hollowphacoemulsification cutting tip, such as the TURBOSONICS tip availablefrom Alcon Laboratories, Inc., Fort Worth, Tex. Tube 30 may be anysuitably sized tube to fit within needle 28, for example 29 gaugehypodermic needle tubing.

As best seen in FIG. 5, tube 30 is free on the distal end and connectedto boiling or pumping chamber 42 on the proximal end. Tube 30 andpumping chamber 42 may be sealed fluid tight by any suitable meanshaving a relatively high melting point, such as a silicone gasket, glassfrit or silver solder. Fitting 44 holds tube 30 within bore 48 ofaspiration horn 46. Bore 48 communicates with fitting 20, which isjournaled into horn 46 and sealed with O-ring seal 50 to form anaspiration pathway through horn 46 and out fitting 20. Horn 46 is heldwithin body 12 by O-ring seal 56 to form irrigation tube 52 whichcommunicates with irrigation tube 18 at port 54.

As best seen in FIG. 7, in a first embodiment of the present invention,pumping chamber 42 contains a relatively large pumping reservoir 43 thatis sealed on both ends by electrodes 45 and 47. Electrical power issupplied to electrodes 45 and 47 by insulated wires, not shown. In use,surgical fluid (e.g. saline irrigating solution) enters reservoir 43through tube 34 and check valve 53, check valves 53 being well-known inthe art. Electrical current (preferably Radio Frequency AlternatingCurrent or RFAC) is delivered to and across electrodes 45 and 47 becauseof the conductive nature of the surgical fluid. As the current flowsthrough the surgical fluid, the surgical fluid boils. As the surgicalfluid boils, it expands rapidly out of pumping chamber 42 through tube30 (check valve 53 prevents the expanding fluid from entering tube 34).The expanding gas bubble pushes the surgical fluid in tube 30 downstreamof pumping chamber 42 forward. Subsequent pulses of electrical currentform sequential gas bubbles that move surgical fluid down tube 30. Thesize and pressure of the fluid pulse obtained by pumping chamber 42 canbe varied by varying the length, timing and/or power of the electricalpulse sent to electrodes 45 and 47 and by varying the dimensions ofreservoir 43. In addition, the surgical fluid may be preheated prior toentering pumping chamber 42. Preheating the surgical fluid will decreasethe power required by pumping chamber 42 and/or increase the speed atwhich pressure pulses can be generated.

As best seen in FIGS. 8-10, in a second embodiment of the presentinvention, handpiece 110 generally includes body 112, having powersupply cable 113, irrigation/aspiration lines I 15, pumping chambersupply line 117. Distal end 111 of handpiece 110 contains pumpingchamber 142 having a reservoir 143 formed between electrodes 145 and147. Electrodes 145 and 147 are preferably made from aluminum, titanium,carbon or other similarly conductive materials and are electricallyinsulated from each other and body 112 by insulating layer 159 such asanodized layer 159 formed on electrodes 145 and 147. Anodized layer 159is less conductive than untreated aluminum and thus, acts as anelectrical insulator. Electrodes 145 and 147 and electrical terminals161 and 163 are not anodized and thus, are electrically conductive.Layer 159 may be formed by any suitable insulating or anodizationtechnique, well-known in the art, and electrodes 145 and 147 andelectrical terminals 161 and 163 may be masked during anodization ormachined after anodization to expose bare aluminum. Electrical power issupplied to electrodes 145 and 147 through terminals 161 and 163 andwires 149 and 151, respectively. Fluid is supplied to reservoir 143through supply line 117 and check valve 153. Extending distally frompumping chamber 142 is outer tube 165 that coaxially surroundsaspiration or inner tube 167. Tubes 165 and 167 may be of similarconstruction as tube 30. Tube 167 is of slightly smaller diameter thantube 165, thereby forming an annular passage or gap 169 between tube 165and tube 167. Annular gap 169 fluidly communicates with reservoir 143.

In use, surgical fluid enters reservoir 143 through supply line 117 andcheck valve 153. Electrical current is delivered to and acrosselectrodes 145 and 147 because of the conductive nature of the surgicalfluid. As the current flows through the surgical fluid, the surgicalfluid boils. As the surgical fluid boils, it expands rapidly out ofpumping chamber 142 through annular gap 169. The expanding gas bubblepushes forward the surgical fluid in annular gap 169 downstream ofpumping chamber 142. Subsequent pulses of electrical current formsequential gas bubbles that move or propel the surgical fluid downannular gap 169.

One skilled in the art will recognize that the numbering in FIGS. 8-10is identical to the numbering in FIGS. 1-7 except for the addition of“100” in FIGS. 8-10.

As best seen in FIGS. 11-13, in a third embodiment of the presentinvention, handpiece 210 generally includes body 212, having powersupply cable 213, irrigation/aspiration lines 215, pumping chambersupply line 217. Distal end 211 of handpiece 210 contains pumpingchamber 242 having a reservoir 243 formed between electrodes 245 and247. Electrodes 245 and 247 are preferably made from aluminum andelectrically insulated from each other and body 212 by anodized layer259 formed on electrodes 245 and 247. Anodized layer 259 is lessconductive than untreated aluminum and thus, acts as an electricalinsulator. Electrodes 245 and 247 and electrical terminals 261 and 263are not anodized and thus, are electrically conductive. Layer 259 may beformed by any suitable anodization technique, well-known in the art, andelectrodes 245 and 247 and electrical terminals 261 and 263 may bemasked during anodization or machined after anodization to expose barealuminum. Electrical power is supplied to electrodes 245 and 247 throughterminals 261 and 263 and wires 249 and 251, respectively. Fluid issupplied to reservoir 243 though supply line 217 and check valve 253.Extending distally from pumping chamber 242 is outer tube 265 thatcoaxially surrounds aspiration or inner tube 267. Tubes 265 and 267 maybe of similar construction as tube 30. Tube 267 is of slightly smallerdiameter than tube 265, thereby forming an annular passage or gap 269between tube 265 and tube 267. Annular gap 269 fluidly communicates withreservoir 243.

In use, surgical fluid enters reservoir 243 through supply line 217 andcheck valve 253. Electrical current is delivered to and acrosselectrodes 245 and 247 because of the conductive nature of the surgicalfluid. As the current flows through the surgical fluid, the surgicalfluid boils. The current flow progresses from the smaller electrode gapsection to the larger electrode gap section, i.e., from the region oflowest electrical resistance to the region of higher electricalresistance. The boiling wavefront also progresses from the smaller tothe larger end of electrode 247. As the surgical fluid boils, it expandsrapidly out of pumping chamber 242 through annular gap 269. Theexpanding gas bubble pushes forward the surgical fluid in annular gap269 downstream of pumping chamber 242. Subsequent pulses of electricalcurrent form sequential gas bubbles that move or propel the surgicalfluid down annular gap 269.

One skilled in the art will recognize that the numbering in FIGS. 11-13is identical to the numbering in FIGS. 1-7 except for the addition of“200” in FIGS. 11-13.

As best seen in FIGS. 14-20, a variety of different distal tips may beused with the handpiece of the present invention. For example, asillustrated in FIGS. 14-16, tip 600 may contain distal end 602 having aplurality of discharge orifices 604. Orifices 604 may be arranged in adivergent pattern, as illustrated in FIG. 14, a convergent pattern, asillustrated in FIG. 15, or in a non-converging, near miss pattern, asillustrated in FIG. 16, depending upon the targeted tissue and thedesired surgical outcome. The converging streams create a high pressureregion where the streams meet, producing a zone of maximumliquefracture. The diverging streams exhibits maximum average pressuredirectly in front of tip 600, making that the most efficientliquefracture zone in that region. The near miss streams create a regionof high shear between the streams, which can contribute to shearfracture of the material in the proximity of tip 600. One skilled in theart will recognize that orifices 604 may be arranged so as to create thedesigned pattern external to tip 600 or internal to bore 611. Distal end602 may be formed, for example by crimping the ends of tubes 165 and167, or 265 and 267, respectively (as illustrated in FIGS. 19 and 20) sothat annular gap 169 or 269 is in fluid communication with orifices 604.One skilled in the art will recognize that tip 600 may be formed as aseparate piece and press fit or otherwise attached to tubes 165 and 167or 265 and 267 so that tips 600 may be interchangeable. For example,different tip 600 designs may be desired during different portions of asurgical procedure.

Alternatively, as illustrated in FIG. 17, tip 600′ may be closed ondistal end 602′ so that discharge orifices 604′ project fluid to thetargeted tissue, but tip 600′ performs no aspiration finction.

As seen in FIGS. 18 and 19, distal end 602″ of tip 600″, in addition todischarge orifices 604″ projecting forward and outward discharge streams611, may contain orifice or orifices 606 that discharge a fluid stream610 rearward into aspiration bore 608. Stream 610 helps to assure thatbore 608 does not become occluded at end 602″.

While several embodiments of the handpiece of the present invention aredisclosed, any handpiece producing adequate pressure pulse force,temperature, rise time and frequency may also be used. For example, anyhandpiece producing a pressure pulse force of between 0.02 grams and20.0 grams, with a rise time of between 1 gram/second and 20,000grams/second and a frequency of between 1 Hz and 200 Hz may be used,with between 10 Hz and 100 Hz being most preferred. The pressure pulseforce and frequency will vary with the hardness of the material beingremoved. For example, the inventors have found that a lower frequencywith a higher pulse force is most efficient at debulking and removingthe relatively hard nuclear material, with a higher frequency and lowerpulse force being useful in removing softer epinuclear and corticalmaterial. Infusion pressure, aspiration flow rate and vacuum limit aresimilar to current phacoemulsification techniques.

As seen in FIGS. 20A and 20B, the inventors have determined that thecoherence length of the fluid stream is affected by many factors,including the properties of the fluid, ambient conditions, orificegeometry, flow regime at the orifice and pressure of the fluid. Byvarying the operating parameters of the system (eg., pressure,temperature, flow development), the coherence length of the fluid pulsestream can be varied. Tip 700 contains orifice 704 internal to bore 708.When operated at relatively high pressures, as shown in FIG. 20A, thecoherence length of discharge stream 711 is relatively short, degradinginternal to bore 708 around distal end 702. As seen in FIG. 20B, whenoperated at relatively low pressures, the coherence length of dischargestream 711 is relatively long, degrading external to bore 708, pastdistal end 702. For example, a pressure stream having a coherence lengthof approximately between −1.0 millimeters and +5.0 millimeters fromdistal end 702 is suitable for use in ophthalmic surgery.

As seen in FIG. 21, one embodiment of control system 300 for use inoperating handpiece 310 includes control module 347, power gain RFamplifier 312 and function generator 314. Power is supplied to RFamplifier 312 by DC power supply 316, which preferably is an isolated DCpower supply operating at several hundred volts, but typically ±200volts. Control module 347 may be any suitable microprocessor, microcontroller, computer or digital logic controller and may receive inputfrom operator input device 318. Function generator 314 provides theelectric wave form in kilohertz to amplifier 312 and typically operatesat around 450 kHz or above to help minimize corrosion.

In use, control module 347 receives input from surgical console 320.Console 320 may be any commercially available surgical control consolesuch as the LEGACY® SERIES TWENTY THOUSAND® surgical system availablefrom Alcon Laboratories, Inc., Fort Worth, Tex. Console 320 is connectedto handpiece 310 through irrigation line 322 and aspiration line 324,and the flow through lines 322 and 324 is controlled by the user viafootswitch 326. Irrigation and aspiration flow rate information inhandpiece 310 is provided to control module 347 by console 320 viainterface 328, which may be connected to the ultrasound handpiececontrol port on console 320 or to any other output port. Control module347 uses footswitch 326 information provided by console 320 and operatorinput from input device 318 to generate two control signals 330 and 332.Signal 332 is used to operate pinch valve 334, which controls thesurgical fluid flowing from fluid source 336 to handpiece 310. Fluidfrom fluid source 336 is heated in the manner described herein. Signal330 is used to control function generator 314. Based on signal 330,function generator 314 provides a wave form at the operator selectedfrequency and amplitude determined by the position of footswitch 326 toRF amplifier 312 which is amplified to advance the powered wave formoutput to handpiece 310 to create heated, pressurized pulses of surgicalfluid.

Any of a number of methods can be employed to limit the amount of heatintroduced into the eye. For example, the pulse train duty cycle of theheated solution can be varied as a function of the pulse frequency sothat the total amount of heated solution introduced into the eye doesnot vary with the pulse frequency. Alternatively, the aspiration flowrate can be varied as a function of pulse frequency so that as pulsefrequency increases aspiration flow rate increases proportionally.

This description is given for purposes of illustration and explanation.It will be apparent to those skilled in the relevant art that changesand modifications may be made to the invention described above withoutdeparting from its scope or spirit. For example, it will be recognizedby those skilled in the art that the present invention may be combinedwith ultrasonic and/or rotating cutting tips to enhance performance.

We claim:
 1. A liquefracture handpiece, comprising: a) a body; b) aninner tube coaxially mounted within an outer tube so as to form anannular gap between the inner tube and the outer tube, the inner tubeand the outer tube being sealed at a distal end; c) at least one orificeat the distal end; and d) a pumping chamber mounted within the body, thepumping chamber formed by a pair of electrodes that allow electricalcurrent to flow across the electrodes when a surgical fluid is containedwithin the pumping chamber, the pumping chamber being in fluidcommunication with the annular gap.
 2. The handpiece of claim 3 whereinsurgical fluid is boiled in the boiling chamber, propelled down theannular gap and out of the orifice.
 3. The handpiece of claim 1 whereinthe electrodes contain an anodized layer.
 4. The handpiece of claim 1wherein the electrical current flowing across the electrodes is capableof boiling the surgical fluid.
 5. The handpiece of claim 4 wherein theboiling surgical fluid is propelled down the annular gap.
 6. Thehandpiece of claim 1 wherein the handpiece produces a pressure pulseforce of between 0.02 grams and 20.0 grams, with a pressure pulse risetime of between 1 gram/second and 20,000 grams/second.
 7. Aliquefracture handpiece, comprising: a) a body; b) an inner tubecoaxially mounted within an outer tube so as to form an annular gapbetween the inner tube and the outer tube, the inner tube and the outertube being sealed at a distal end; c) at least one orifice at the distalend; and d) a pumping chamber mounted within the body, the pumpingchamber having a pair of electrodes that allow electrical current toflow across the electrodes when a surgical fluid is contained within thepumping chamber, the pumping chamber being in fluid communication withthe annular gap and produces a pressure pulse force of between 0.02grams and 20.0 grams, with a pressure pulse rise time of between 1gram/second and 20,000 grams/second.
 8. The handpiece of claim 7 whereinthe electrodes contain an anodized layer.
 9. The handpiece of claim 7wherein the electrical current flowing across the electrodes is capableof boiling the surgical fluid.
 10. The handpiece of claim 9 wherein theboiling surgical fluid is propelled down the annular gap.